Recovery of valuable gases in the sulfite process.



No. 853,936. PATENTBD OCT. 23, 1906.

, MORTBRUD,

RECOVERY OF VALUABLE GASES 'IN THE SULFITE PROCESS. APPLICATION FILE D JAN. 8. 1906.

mm m o EINAR MORTERUD, OF CHRISTIANIA, NORWAY.

RECOVERY ,OF VALUABLE GASES IN THE SULFITE PROCESS.

Specification of Letters Patent.

Patented Oct. 23, 1906.

Application filed January 8, 1906. Serial No. 295,140.

To all whom it may concern:

Be it known that I, EINAR MORTERUD, a

subject of the King of Norway, residing at Chrlstlania, Norway, have invented certain new and useful Improvements in the Recovery of Valuable Gases in the Sulfite Process; and I do hereby decare the following to be a full, clear, and exact descri tion of the invention, such as will enable 0t ers skilled in the art to which it appertains to make and use the same, reference being had to the accompa'nying drawing, and to letters of reference marked thereon, which forms apart of thisspecification.

My invention relates to a process for regeneration ofv valuable gases and of heat in the manufacture of cellulose according to the sulfite process.

The digester of a sulfite process plant when the cooking of thestockis finished contains a reat dealof liquidunder high pressure. hen" the digester is being emptied, this liquid will, to a reat extent, evaporate, and the steam and 51 free' will escape. In this manner considerable quantities of heat and of sulfurous acid will get lost.

According to 'my invention these losses are prevented by treatingthe'contents of the digester in a peculiar manner, whereby the va uable gases may be athered in a state relatively cold and free 0 steam, so that the i may be utilized anew for preparation of d1- gester solution.

The process may be carried out in the followin manner: "The contents of the digester or on y the liquid and gaseous parts of the same are led to a vessel or a chamber towhich air has not access and in which a pressure is maintained which is referabl below that of the atmosphere. n this 0 amber gas'is liberated from the liquid and the latter 1s partly evaporated or converted. into steam, the remaining liquid containing the incrustations and other matter dissolved during the digesting process. The next step in the process is to separate the ases from the steam and other vapors, and t is is done by means of a condensing apparatus, preferably so constructed that the steam and gas are led into direct contact with water. I prefer to use a circulating uantity of water, the temperature of whic is so regulated that gas is not absorbed therein to any extent worth men tioning. When the gas and steam come in e gases thereby made contact with this water, the major part of the steam will be condensed and taken up by the water, the tem erature of which will thereby be raised and the gas will leave the apparatus relatively free from steam and vapors and holi ing a temperature below the boilingpoint of water. Itmay be directly utilized to produce. sulfite solution, or, if desired, it may first be passed through an apparatus to be cooled somewhat more. The water circulating in the above-mentioned condensing apparatus will, during the circulation, risein temperature from, say, 100 to 180 Fahrenheit and is afterward passed through a cooler, which takes up the absorbed heat and utilizes it for any useful purposefor in' stance, in a heating or drylng ap 'aratus or for preheating the freed water 0 a steamboiler or the digester solution.

In digesting processes inwhich solution is drawn off during the process such solution may be led into the system above described for bein treated in the same manner as the Waste so ution. v

The annexed drawing shows a diagram of a system of apparatus for carrying out my above-described a paratus.

A is a digester; E, a low-pressure chamber, into which the contents of the digester is blown when a charge has been cooked.

D is a condensing apparatus arranged on top the chamber B and correspondin with the latter through a large 0 ening C. a n the condensing apparatus she ves are arranged on which water is spread and flows down in cascades. The water enters through the pipe F, coming from the bottom part of the reservoir E, to which it is again lifted up through the pipe G by means of a centrifugal ump H. The gases leaving the condenser cooler ratus L of a usual t pe. The top of the atter is connected wit a fan M or other suction device, which maintains a suitable low pressurethrough the whole system.

The bottom of the chamber B opens into a channel B, rovided with a water-trap, so that the stoc and solution may run out successively without letting any gases escape. The water-reservoir E is, through pipes O and P, connected with a cooling ap aratus N; by means of which the water used or condensing steam, and thereby raised in temperature, may, when the blowing-off period is finf throu h the pipe I are passed through a K and thence to the absorbing ap a- V perature-say ab out 1 Fahrenheitbefore it is again used in the condensing apparatus;

I claim 1. In the manufacture of sulfite cellulose the process, which consists in discharging the contents of the igester or only the liquiw and gaseous contents of the same into a closed chamber, in which a low pressure (about or below atmospheric pressure) is maintained, drawing ofi the gases and vapors formed in this chamber and passing them through a closed apparatus in cirect contact with water or other suitable liquid of a suitable temperature so as to cause a condensation of the vapors and avoiring an absorption of gases and utilizing the gases so obtained in any suitable way.

' 2. In the manufacture of sulfite cellulose the process, which consists in cischarging the contents of the digester or only the liquid and gaseous contents of the same into a closed chamber, in which a low pressure (about or below atmos heric pressure) is maintained, drawing off 1; e gases and va ors formed in this chamber and passing t em through a closed apparatus in oirect contact with Water or other suitable liquid of a suitable tem erature so as to cause a condensation of the vapors and avoidingan absorption of gases, passing the gases leaving this apparatus through an apparatus containing absorption material for the purpose of obtaining solution for the digestln 1 process.

3. In the manufacture of su? te cellulose the process, which consistsin discharging the contents of the digester or only the liquidand gaseous contents of the same into a closed chamber, in which a low pressure (about or below atmospheric pressure) is maintained, drawing oil the gases and vapors formed in this chamber and passing them through a closed apparatus in cirect contact with water or other suitable liquid of a suitable temperature so as to cause a condensation of the vapors and avoi-ning an absorption of gases passing the obtained heated liquid through an apparatus capable of reducing its temperature and returning the coolel iqui l to the condensing apparatus for treating the next charge in the same manner.

4. In the manufacture of sulfite cellulose, the process which consists in discharging the contents of the digester, or only the liquid and gaseous contents of the same, into a close 1 chamber in which a suitably-low pressure is maintained, drawing off the gases and water-vapor, con? ensing the Water-vapor without absorbing appreciable quantities of gases, and finally recovering the gases for treatment of the next charge, substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention I have signerl. my name in presence of two subscribing witnesses.

EINAR MORTERUD.

Witnesses HENRY BORDEWIOH, Arie. OLSEN. 

